I don't think it's possible to not have flesh unless you're a robot. I don't think it will ever be possible to get rid of all your flesh but maybe in the future there will be technology to get rid of most of it and replace it with synthetic parts, tough at most the brain is one thing that can't really be replaced with a robotic equivalent.
Whoops, thought this was one of those NonBinary or otherkin moments (you know the ones about wanting to shed one's mortal flesh and become an etherial being).
Should've probably been obvious to me though.